1) Yes.

2) An overwhelming majority of studies published in peer-reviewed scientific journals supports that the climate is warming and that it is due in great part to human activity.

3) Any international panel of anything is going to have political motivations. Rather than reading the overall summary, it is better to look at individual studies and do your own broad spectrum analysis -- what are the goals of these studies, who is paying for them, are the methods sound and the conclusions well-supported, etc.

4) Most of those who are trying to make a public case are doing a poor job of it, making too many emotional appeals with doomsday scenarios and not simply presenting the ample evidence in their favor in a clear and concise manner. I've been to two presentations recently from professors who have been in the field for decades -- they've worked with this for a long time and were able to just show a clear picture without pulling on heartstrings. That's what finally convinced me, and it's what needs to happen on a more frequent basis if the debate is going to get anywhere. As for opponents of the AGW theory, most of them are motivated by selfish interests. A lot of the evidence against AGW comes from groups formed by companies who stand to lose a lot if AGW is widely accepted. They receive equal media coverage as proponents because the media wants to portray itself as "fair and balanced" to attract as many viewers as possible.

5) Hundreds of links over many years did nothing to convince me one way or another, it's not going to convince you. The truth is out there, and if you want to know, it isn't difficult to find out.

In response to Kytiara:

Everything in science is a theory. Einstein's Theory of Relativity, Darwin's Theory of Natural Selection, quantum mechanics, plate tectonics, it's all theory. In order to be a theory, a model must be falsifiable, which means it can be disproven. Theory can never be proven, it can only be supported by an overwhelming amount of evidence.

A few degrees Celsius can make a big difference. The difference in average global temperature between today and the last ice age is about 6 or 7 degrees Celsius. That's the difference between New York City as it is today, and a mile of ice covering NYC. The 25 million number you mentioned will only get higher if there are significant climate changes in areas where people don't have the technology to readily adapt.

As far as why we should be spending money on this -- a lot of things we need to do to slow our contribution to GW are things that will be beneficial to our society. The reason this has not happened is because a a small number of companies who are fairly big political heavyweights stand to lose a lot during the transition. As a whole, we would be much better off if we were using renewable energy sources instead of being dependent on foreign sources. The amount of work it will take to build a new infrastructure is going to create far more jobs than will be lost by a few companies. The difficulties that the average consumer will face in adapting to these changes in infrastructure will be more than offset by overall economic growth. Even if you don't believe that the planet needs to be saved, it's easy to see that these are sound policies anyway!

EDIT: I'd like to add that this has been a refreshing thread.  With the level of fanboy arguments seen on the rest of the forum, I expected a global warming thread to be completely berserk.  It seems exactly the opposite, the level of discussion is much higher here than in most threads.

I've been browsing the main page here and saw this topic which I think is very interesting so I thought I'd contribute. It also seems that Gballzack is banned, so I'm happy

Well, first I'd like to say there is a human contribution to the global warming, but people are horribly misguided in certain issues and I'll try to explain about these things as clearly as possible.

This is one popular myth. Virtually no scientist thinks this can happen because Europe gains its warmth mostly from winds and both the winds and Gulf-stream are mostly driven by Coriolis force, which results from the rotation of the Earth, not the thermo-haline circulation. So to stop Europe from getting warmth from the lower lattitudes, the rotation of the Earth would have to be stopped.

There's also some other topics where people have been misguided by the sensation-seeking media imo. For example, it's no clear how much the hurricane activity will rise because of global warming. In the year 2005 there was a record amount of them and the media was full of stories linking the record to climate change but the scientists are far more careful. When no hurricanes hit the coast of US in 2006, the media seemed to go silent about the issue. Christopher Landsea, an expert on hurricanes, says the hurricane intensity may rise 1-2% in the next 100 years.

There have also been stories of malaria spreading because of global warming, but that seems far-fetched, because believe it or not, malaria is not purely tropic disease. The malaria mosqitoes were abundant for example here in Finland and east in russia, even Siberia in the 19th century. The malaria started to lose ground after increased level of hygiene. In southern Europe people got finally rid of malaria by drying up bogs and using DDT in the 60s.

The vast ice sheets of West Antarctica and Greenland will NOT melt in 100 years, not even in 1000 years even if the World would warm up according to the worst scenarios. That's simply because the require so much energy to melt. If the melting is slow enough, the ocean floor will adapt to the added weight and so the continents will rise relative to the ocean floor, which results in very little rise in sea-level. The IPCC (Intergovernmental Panel on Climate Change) predicts rise of 20-60 cm from 1990 to 2100.

As far as the main argument of AGW goes, it's clear that greenhouse gases warm up the atmosphere, but again, there is not certainity of how much. IPCC states that the climate sensitivity, that is, the rise of temperature resulting from doubling the amount of CO2, is 1.4-5.5 degrees celsius. Now you may think that it doesn't matter how strong the effect is, because the cumulation keeps on going. (I agree that we should get rid of fossil fuels as soon as possible because that has to be done at some point anyway (they don't last forever), so my points aren't meant to encourage polluting more.)

However, the climate sensitivity works on a logarithmic base. That is, the doubling of the amount of CO2 in atmosphere results in very similar rise in temperature no matter what the starting values are. For example, if the rise from 200 ppm to 400 ppm would raise the temperature by X degrees, so would the rise from 2000 ppm to 4000 ppm. This means that we would most probably die off because of CO2-poisoning before we could make this planet too hot to live due to increased CO2-levels. In addition, there has been as far as 20 times more CO2 in the atmosphere compared to the levels of today and the time is known as the Ordovician glaciation period, one of the coldest epochs ever.  That would suggest that the Earth's climatic balance is not easily altered by rise in greenhouse gases.

Some of you might have now thought that why has the climate warmed so little if the percentual increase of greenhouse gases is the one that matters. That surely has been a big problem. The warming should have been fastest from 1950-1970 because of the high forcing, but instead there was no rise in temperature at all in that period. This is explained with global dimming, which results from increased pollution. Now that the technique is cleaner, less pollution is created and the Earth should warm faster. However, the warming hasn't been very fast after year 2000. Here's a graph to show what I mean: http://www.cru.uea.ac.uk/cru/data/temperature/_nhshgl.gif

This might be due to the stabilizing of methane levels or solar activity, for example. We'll see how the climate keeps changing.

First: I agree with you, that the most catastrophic scenarios will not become true. There will be more storms, droughts and people will dying in lesser developed countries and in higher developed countries the economy will be hurted. But the mankind will exist on. But these sentences about CO2 and it's effects to climate are mere simplifications. Climate changes dont happen over night. So the pollution we did in 19th century (yes back then) will influence climate in the next years. The Emissions in the 20th century will need hundred years or more, to show their full effects on climate. Thats why the european countries no longer want to avoid global warming (it's already impossible), they want to reduce it to 2 degrees. And to the Ordovicium-argument: Climate change is not linear. There were always warm and cold periods in earths history. But, the general trend is, that the earth is cooling down, as plants converts the CO2 into oxygen.

Personally, I don't know whether there is any significant long term warming occuring on the earth and even if there is to what extent it is effected by man's actions. The science is far from a consensus although there is far more effort in attempting to prove and predict global warming than there is about disproving it, on top of that any information which conflicts the assumption that Global warming is occuring is generally not reported on; this leaves us with the impression that there is no one in the scientific community who doesn't believe in man made global warming.

I do know that we're being manipulated to believe in global warming for reasons that have little to do with the planet. Al Gore stands to make hundreds of millions of dollars if he can convince people, companies and governments that Global Warming is an issue because he is one of the primary investors in a carbon trading firm. In Canada and the United States there is the motivation to make Global Warming a major political issue in the upcomming elections because it is believed that Liberals and Democrats are stronger on the issue than the Conservatives and Republicans.

As for Environmental lobby groups they should generally not be trusted. Patrick Moore (a founder and former president of Greenpeace) had the following to say:

"See, I don't even like to call it the environmental movement any more, because really it is a political activist movement, and they have become hugely influential at a global level"

"By the mid-1980s, the environmental movement had abandoned science and logic in favor of emotion and sensationalism. I became aware of the emerging concept of sustainable development: balancing environmental, social and economic priorities. Converted to the idea that win-win solutions could be found by bringing all interests together, I made the move from confrontation to consensus"

Anyways, one more quote from Patrick Moore on this subject which I think is appropriate:

"It's become so complicated, there's so much snake oil around the whole subject... the best comment that was ever made was by Michael Crichton in his book State of Fear: 'I am certain there is too much certainty in the world'. And I am certain that he is right"

1. Yes.

2. Earth, as a way of stabilization, goes through cyclic periods of global warming naturally, by itself. However, the rate of the Earth going into global warming has drastically increased during the years that humans were present on earth. It should be obvious that the human race has an impact on Global Warming. I believe in Science as well as Nescience (non science). Humans cannot be classified as natural with such a negative impact on the Earth.

3. I don't know the IPCC

4. They are out of thier minds i think. Most of them fail to see the facts i think, and some are stuck in the "Earth lasted only 8000 years" thing.

5. I don't have much links, but most scientists are in agreements, as well as historical facts.

Well, there is. It can be seen from the satellite data and weather station data as well as in melting glaciers. The meltdown will continue for a long time as it is also one of the delayed effects Mnementh mentioned. The huge East Antarctica is so large and isolated that it's gaining mass though because of increased precipitation.

Actually ...

"Unlike the surface-based temperatures, global temperature measurements of the Earth's lower atmosphere obtained from satellites reveal no definitive warming trend over the past two decades. The slight trend that is in the data actually appears to be downward. The largest fluctuations in the satellite temperature data are not from any man-made activity, but from natural phenomena such as large volcanic eruptions from Mt. Pinatubo, and from El Niño. So the programs which model global warming in a computer say the temperature of the Earth's lower atmosphere should be going up markedly, but actual measurements of the temperature of the lower atmosphere reveal no such pronounced activity."

<a href="http://science.nasa.gov/NEWHOME/headlines/essd06oct97_1.htm">Source: NASA</a>

A very disturbing thing in the entire global warming debate is that satellite data is being ignored in favour of far less accurate surface data. Just as a side note, why are the skeptics always far better informed than the believers in the Global Warming debate?

Yulegoat said: That's intellectual dishonesty. The article you presented is dated 1997 and in 1998 the overall trend started to be visible in the satellite measurements too.

Except you're wrong once again:

"For many years now, human-caused climate change has been viewed as a large and urgent problem. In truth, however, the biggest part of the problem is neither environmental nor scientific, but a self-created political fiasco. Consider the simple fact, drawn from the official temperature records of the Climate Research Unit at the University of East Anglia, that for the years 1998-2005 global average temperature did not increase (there was actually a slight decrease, though not at a rate that differs significantly from zero). "

<a href="http://www.telegraph.co.uk/opinion/main.jhtml?xml=/opinion/2006/04/09/do0907.xml">Source</a>

Both satelite and ground based measurements from 1998 to 2006 demonstrated no warming trend. Essentially, we have data from well known published and peer reviewed papers which demonstrates that we have had not had temperature increases in the period where people claim we have had "Global Warming".

HappySqurriel said: Yulegoat said: That's intellectual dishonesty. The article you presented is dated 1997 and in 1998 the overall trend started to be visible in the satellite measurements too. Except you're wrong once again: "For many years now, human-caused climate change has been viewed as a large and urgent problem. In truth, however, the biggest part of the problem is neither environmental nor scientific, but a self-created political fiasco. Consider the simple fact, drawn from the official temperature records of the Climate Research Unit at the University of East Anglia, that for the years 1998-2005 global average temperature did not increase (there was actually a slight decrease, though not at a rate that differs significantly from zero). " Source Both satelite and ground based measurements from 1998 to 2006 demonstrated no warming trend. Essentially, we have data from well known published and peer reviewed papers which demonstrates that we have had not had temperature increases in the period where people claim we have had "Global Warming".

In the first message you talked about long-term climate trend from satellite measurements and it is +0.13 celsius per decade, as can be seen from the pic I posted. There are marked annual variations of course, but the overall trend is positive.

The latest satellite data can be found from here: http://pm-esip.msfc.nasa.gov/amsutemps/

In addition to the troposphere warming, the stratosphere has cooled, which is a sign of greenhouse warming.